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This French Onion Chicken Casserole features cauliflower and tender chicken breast pieces, covered with caramelised onions and a creamy sauce. It’s baked with a topping of melty cheddar cheese for the ultimate comforting dinner recipe.
While French onion soup is surely one of the ultimate cozy dinner recipes for winter and fall, this casserole takes things to a new level of delicious. I’ve added juicy pieces of chicken breast and chunks of cauliflower into the mix with caramelised onions which are layered with cream of mushroom soup. This is all baked up with a layer of cheddar or gouda cheese on top to create such a simple yet delicious recipe.
For more cozy casseroles, try this Chicken, Broccoli & Rice Casserole or my Harvest Chicken Casserole.
Recipe Overview
Ingredients Needed
Below are the ingredients you’ll need to make this French Onion Chicken Casserole. Full quantities can be found in the recipe card further down in the post.
- Olive oil: You can also use avocado oil if you prefer.
- Yellow onions: The yellow onions have a good level of natural sweetness, which is brought out by slowly cooking them until caramelised. I do not recommend using red onions as they’ll make the color unappealing.
- Chicken breast: I like to use chicken breast cut into bite-sized pieces so that the casserole cooks quickly and is easy to prep. You can use diced boneless, skinless chicken thighs for a richer flavor. See note in recipe card for substitution option.
- Kosher salt and pepper
- Cauliflower: The florets of cauliflower bake with the creamy sauce, onions, and chicken, absorbing a ton of flavor and softening. This keeps the casserole lower-carb (instead of using bread or potatoes) while still being satisfying.
- Cream of chicken soup: This forms the savoury, creamy sauce for the casserole with minimal fuss. Choose an organic canned soup for the best flavor. Pacific Foods offers a great creamed chicken soup made with clean ingredients that I enjoy using.
- Cheddar or gouda cheese: I like to shred the cheese myself as it melts better than the pre-shredded cheese from the store. Cheddar has a stronger cheesey flavour while gouda is milder and gooier.
How to Make French Onion Chicken Casserole
First, preheat the oven to 350°F.
Step 1: Cook the onions in the olive oil over a medium heat, stirring often, until golden (around 12-15 minutes).
✏️ If you have some extra time and want a stronger onion flavor, you can lower the heat and keep cooking the onions for 20-30 minutes longer to let them turn a deep golden color.
Step 2: Cut the cauliflower into florets and add to a 9×13-inch casserole dish, season with salt and pepper.
✏️ Try to cut the florets into evenly sized pieces so that they all cook at the same rate.
Step 3: Add the pieces of chicken breast to the skillet and sautee until half cooked, around 6-8 minutes.
✏️ By part-cooking the chicken now, it will prevent it from overcooking and becoming dry when you bake the casserole.
Step 4: Spoon the chicken-onion mixture over the cauliflower in the casserole dish. Pour over the cream of chicken soup, cover with aluminum foil, and bake for 30-35 minutes until the cauliflower is fork-tender.
✏️ Covering the casserole with foil for the first part of the bake prevents it from drying out and helps the cauliflower to steam and cook.
Step 5: Remove the foil, sprinkle the cheese over the casserole, and return to the oven for a further 15 minutes.
✏️ You just want the casserole to go back into the oven for long enough to melt the cheese and let it brown a little.
Step 6: Serve the casserole with crusty bread for scooping up the sauce.
Variations
- Add some greens: Swap all or half of the cauliflower for broccoli florets
- Speed it up: For an even quicker casserole, use shredded rotisserie chicken in place of the chicken breast.
- Change the cheese: French onion soup is typically garnished with a slice of bread topped with melted gruyere cheese. If you can find it, use grated gruyere on the top of this casserole for that classic flavor.
Common Questions
If you rather not use canned creamed chicken soup, then use 1 and 1/2 cup broth/stock with 1-1/2 tbsp cornstarch and 8-ounces cream cheese (softened, at room temp to help emulsify). Should be blended until smooth, then added to the casserole.
Yes! Allow the baked casserole to cool completely then wrap the whole dish in plastic wrap followed by a layer of aluminum foil and freeze. Alternatively, transfer leftovers to an airtight container and freeze. It can be frozen for up to 3 months.
I like to serve it with crusty bread for soaking up the sauce. If you’d like to try making some bread to go with it, my Italian Focaccia recipe won’t disappoint! Alternatively, it’s delicious with a side of creamy mashed potatoes or some sauteed green beans.
Yes you can. Follow the recipe but cook the chicken breast chunks fully before layering them over the cauliflower in the dish. Once the cauliflower, chicken, onions and soup are all layered in the dish, cover tightly with foil and refrigerate for up to 24 hours before baking as usual.
Allow the baked casserole to cool completely, transfer leftovers to an airtight container and chill in the fridge for up to 3 days.
You May Also Like
- Cowboy Casserole
- Buffalo Chicken Casserole
- Cabbage Roll Casserole
- Shredded Chicken Tacos
- Chicken Noodle Casserole
- Baked Spaghetti
- French Onion Pasta
- French Onion Chicken Skillet
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French Onion Chicken Casserole
Ingredients
- 2 tbsp olive oil
- 3 large yellow onions, sliced
- 1 pound chicken breast, cut into bite sized pieces
- Kosher salt and pepper, to taste
- 1 large cauliflower head, cut into bite sized florets
- 30 ounces cream of chicken soup, 2 x 15oz can, see note
- 1 cup cheddar or gouda cheese, shredded
Instructions
- Preheat the oven to 350°F.
- Heat the 2 tbsp olive oil in a large skillet over medium heat. Add the 3 large yellow onions (sliced) and sautee,stirring frequently until golden and lightly caramelized, about 12-15 minutes.
- Meanwhile, cut the 1 large cauliflower head into bite-sized florets and place them in a 9×13-inch casserole dish. Sprinkle it with some salt and pepper.
- Once the onions are done, add in the 1 pound chicken breast (cut into bite-sized pieces) and season with salt and pepper. Cook until the chicken is half-cooked and mostly no longer pink, about 6-8 minutes.
- Add the mixture to the cauliflower. Pour the 30 ounces cream of chicken soup. Cover the dish with aluminum foil and bake for 30-35 minutes, until the cauliflower is just fork-tender.
- Uncover, sprinkle with the 1 cup cheddar or gouda cheese (shredded), and continue to bake for 15 minutes.
- Serve warm with crusty bread, because there's a lot of delicious creamy sauce in there!
Notes
Tips:
- To replace the creamed chicken soup: If you would rather not use canned creamed chicken soup, then use 1 and 1/2 cups broth/stock with 1-1/2 tbsp cornstarch and 8-ounces cream cheese (softened, at room temp to help emulsify). Should be blended until smooth, then added to the casserole.
- Cut the cauliflower into equally sized florets so that they cook at the same rate.
- Keep an eye on the onions and stir them often as they cook so that they don’t catch and burn.
- If the onions are scorching on the bottom of the pan, add a splash of water as they cook. This will help you scrape up any crusty bits from the bottom of the pan and help the onions brown more evenly.
- Briefly cooking the chicken locks in moisture and prevents it from overcooking as the casserole bakes.
- Let the casserole cool for 5-10 minutes before serving, as it will be very hot straight from the oven!
Storage:
- Fridge: Allow the baked casserole to cool completely, transfer leftovers to an airtight container, and chill in the fridge for up to 3 days.
- Freezer: Allow the baked casserole to cool completely. Wrap the whole dish in plastic wrap, followed by a layer of aluminum foil, and freeze. Alternatively, transfer leftovers to an airtight container and freeze. It can be stored in the freezer for up to 3 months. Allow to thaw overnight in the fridge before removing the plastic wrap and reheating.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
